Uh oh

[rahangman]

Took a quick little trip with bus up to Branson today, about 40miles each way. On return trip with outside temps pushing 100, noticed my Water Temp approaching 210 and went almost to 220. I stopped and while still idling fine, noticed temp starting to recede back down to usual 190-195 and holding steady at ide. Started backup, noticed on long pulls up hills that temp would rise, but then on downward side would recede again down to about 200. Stopped again for about 10mins this time and temp went right on down around 160 and held steady. Got home and put the bus away, but forgot to check coolant level. Needless to say, I will in early AM. I am thinking a stuck , or sticking thermostat. Sorry for not thinking to check level, but it was so stinking hot I just wanted into house air conditioning. Over temp never actuated (if I have one).:eek: Oh, by the way, it is an 8V of course

[truk4u]

Rodger,

It could be anything from the thermostat, fan, radiator to a bad gauge. I mention gauge since you said it went down to 160 which is probably an inaccurate reading. I know mine won't ever go below 170 while idling in the heat and I've checked it with the heat gun. Mine stays below 195 even in hot temperatures, but I don't let it get any hotter by gearing down if necessary and always keeping the Pyro's in the 900 range. You may hear that the Pyro's are useless, but keeping the EGT under 1000 will help the heat problem. 210 to 220 I believe would be turning on the check engine light and you didn't mention that. I also assume your coolant level was OK because you didn't get any light.

I would get it checked out, since high temps on the 8V's will for sure lead to trouble. The integrity of the cooling system on the 8V's is a must and you probably don't have any history as to how the cooling system has been maintained. Do you know if the coolant SCA has been maintained to prevent cavitation? Check the oil and make sure your not making any oil (coolant in the oil).

Lets keep in mind the 8V's will not tolerate the series 60 temperatures, so no sense making temp comparisons other than the 8V's.

[rahangman]

Thanx Tom, I want to check the Coolant Temp "Light", gauge is possibility because I see it "jump" a bit occasionally, erratic which causes me concern. I will also (after AM coffee) check oil to see if I "made" some. I had sampling done on oil and coolant last Oct and all is fine, I added the correct amount/type of additive as the existing coolant , though favorable per sampleing, did not show signs of it. I have some extra sample bottles, so will draw samples today also on both and send them in. I knew about the High Temp and that is why I tried to keep temps down when it seemed that I had some control over it. Any offers as to where relay for Hi Temp is located, anyone?

[truk4u]

I don't have a coolant temp light, just a gauge, so no relay. A high temp condition would turn on my CEL and the DDEC 2 code would be 44. Another thought is to compare your dash gauge against the mechanical temp gauge in the engine compartment to the right of the electrical box. I'm not suggesting the only problem is a gauge, but at least that's an easy one to check before moving on to the other potential causes.

You can buy test strips at DD if that's easier then sending it in. I would focus on what is causing the heat before worrying about testing the coolant.

[LA-HODAG]

Hey, Rodger. As you know, I have a sister ship to yours. Check your coolant level. Hopefully that is it, but my bus won't run if it is down even a gallon. Not sure that amount would cause the problem you describe. A stuck stat is a real possibility. I had one stuck in the transmission and it made both the trans and engine run hot. I don't want to be too negative, but I had to replace my radiator a few years back. Even though the bus had been well maintained by the prior owner, the core was shot after 250k miles. I'm hoping that's not it, as it can be costly.

By the way, according to Prevost Mira Loma, Country Coaches of this vintage have notorious issues with the dash gauges, due mostly to spotty grounds. Maybe not an issue for you since yours has been working ok, but mine has always been funky. Even after changing the radiator, my dash temp. gauge reads 10-20 degrees higher than the temp gauge in the engine compartment at normal operating temp. The dash coolant and oil temp gauges jump up another 10% or so when I turn on the headlights or marker lights, illuminating the dash (obviously a grounding problem that I can't find). Could be that a similar gremlin has just surfaced in yours. You should get a check engine light if you actually get way up there. It happened to me when my radiator was bad, and your bus should have the same DDEC II system. That warning is independent of the dash gauge.

Good luck
Bryan

[rahangman]

Well, Bryan, you seem to have your facts straight. I have also had the "funky" read out on Coolant & Oil Pressure you describe. I turn on my directional and both of those gauges will sit and jump along with the flasher. I am going to fire it up tomarrow and take her for a quick , local sping, to check on the direct reader gauge on the engine and the "indicator" on the dash. Hope that is it, I am starting to assemble Helpers and equipment for a thermostate change and am thinking about a waterpump overhaul at the same time. Thanks for you 2 Cents and same to Truck